如果我以相同的方法执行两个事务，则领域已经处于写入事务中

Question

如果它们超过一定数量，我需要消除领域数据库记录的第一条记录，但我得到了这个异常：

Caused by: java.lang.IllegalStateException: The Realm is already in a write transaction in /Users/cm/Realm/realm-java/realm/realm-library/src/main/cpp/io_realm_internal_OsSharedRealm.cpp line 126
    at io.realm.internal.OsSharedRealm.nativeBeginTransaction(Native Method)
    at io.realm.internal.OsSharedRealm.beginTransaction(OsSharedRealm.java:269)
    at io.realm.BaseRealm.beginTransaction(BaseRealm.java:404)
    at io.realm.Realm.beginTransaction(Realm.java:145)
    at io.realm.Realm.executeTransaction(Realm.java:1491)
    atsavedAddresses(AddressBook.kt:39)````

正如您在下面看到的，我尝试添加commitTransaction，与executeTransactionAsync 和executeTransaction 一起玩，开始交易等。但是尽管我阅读了几篇这样的帖子并且GitHub 发布了cmets，但没有任何效果，我甚至发现这个post 但太抽象了，无法与我的案例相关

init {

    Realm.init(ProActiveApplication.applicationContext())
}


private val realm = Realm.getDefaultInstance()

val query = realm.where(RecentAddress::class.java).findAll()

fun savedAddresses(name: String, address: String) {
   realm.beginTransaction()
    realm.executeTransactionAsync  {
        val addressToSave = realm.createObject(RecentAddress::class.java)
        addressToSave.name = name
        addressToSave.street = address
        Log.d("ME","-----------------")
        Log.d("ME", " CreateTransaction: ${addressToSave.name} in ${addressToSave.street}")
        Log.d("ME","-----------------")
    }
    realm.commitTransaction()
    realm.close()

    realm.beginTransaction()
    realm.executeTransaction {
        if (query.size > 2) {
            val location = query.get(0)
            Log.d("ME","-----------------")

            Log.d("ME", " This is cancelled: ${query.get(0)}")
            Log.d("ME","-----------------")

            location?.deleteFromRealm()

        } }

编辑

按照建议，我将删除 beginTransaction() 和 commitTransaction，我也改为 executeTransaction 而不是 `executeTransactionAsync()

    fun savedAddresses(name: String, address: String) {
   // realm.beginTransaction()
    realm.executeTransaction {
        val addressToSave = realm.createObject(RecentAddress::class.java)
        addressToSave.name = name
        addressToSave.street = address
        Log.d("ME", "-----------------")
        Log.d("ME", " CreateTransaction: ${addressToSave.name} in ${addressToSave.street}")
        Log.d("ME", "-----------------")
    }
   // realm.commitTransaction()
    realm.close()

    // realm.beginTransaction()
    realm.executeTransaction {
        if (query.size > 2) {
            val location = query.get(0)
            Log.d("ME", "-----------------")

            Log.d("ME", " This is cancelled: ${query.get(0)}")
            Log.d("ME", "-----------------")

            location?.deleteFromRealm()

        }

    }

现在我明白了，就像 Realm 将取消第一个 0 位置，但随后将在 0 位置添加下一条记录而不是列表的末尾

如果我取消第二个块executeTransaction，记录按顺序添加成功，但保留第二个块，事务消除第0行，然后在位置0插入第二条记录，而不是在列表的末尾

Answer 1

如果您使用executeTransaction，则无需手动编写beginTransaction() 和commitTransaction()，一切都会为您完成。 所以基本上你 beginTransaction() 然后启动 executeTransaction 块然后你在事务中得到事务，这就是崩溃的原因，你也可以在一个事务中完成所有这些代码。

Answer 2

如果我正确理解您的问题，您希望消除/删除前两条记录（如果有）并在列表末尾插入新记录。 试试这个

fun savedAddresses(name: String, address: String) {
   realm.executeTransaction { realm ->
        val addressToSave = realm.createObject(RecentAddress::class.java)
        addressToSave.name = name
        addressToSave.street = address
        //insert the record at the end of the list 
        realm.insert(addressToSave)
    }
    deleteOldRecords()
}

fun deleteOldRecords() {
    realm.executeTransaction { realm -> 
        val recentAddressList = realm.where(RecentAddress::class.java).findAll()
        if(recentAddressList.size > 2){
            for(i in 0..1) {
                recentAddressList.deleteFromRealm(i)
            }
        }
    }
}

如果我理解错了请纠正我。